[UTILS][TemporaryFile] Change way TemporaryFile takes arguments and it's internal implementation

plugins/ImageEncoder/ImageEncoder.php

@@ -77,7 +77,7 @@ class ImageEncoder extends Plugin
 
         $type      = self::preferredType();
         $extension = image_type_to_extension($type, include_dot: true);
-        $temp      = new TemporaryFile(prefix: null, suffix: $extension); // This handles deleting the file if some error occurs
+        $temp      = new TemporaryFile(['prefix' => 'image', 'suffix' => $extension]); // This handles deleting the file if some error occurs
         $mimetype  = image_type_to_mime_type($type);
         if ($mimetype != $original_mimetype) {
             // If title seems to be a filename with an extension

plugins/VideoEncoder/VideoEncoder.php

@@ -72,7 +72,7 @@ class VideoEncoder extends Plugin
 
         // FFmpeg can't edit existing files in place,
         // generate temporary output file to avoid that
-        $tempfile = new TemporaryFile('gs-outpath');
+        $tempfile = new TemporaryFile(['prefix' => 'video']);
 
         // Generate palette file. FFmpeg explictly needs to be told the
         // extension for PNG files outputs